Twisted paper cord



Oct. 2 6, 1937. J. E. MILLETT 2,097299 g TWISTED PAPER CORD Filed Aug. 17, 1985 Patentea od. 26, 1937 TWISTED PAPER CORD John E. Millett, Chelsea, Mieli., assignor to Grand Rapids Fibre Cord Company, Grand Eapids,

Mich., a4 corporation of Michigan Application August 17, 1935, Serial No. 36,668

3 'Claims.

This invention relates to twisted paper cord. Twisted paper cord is made from an initially fiat strip or ribbon of paper in such manner,.

heretofore, that one or both edges of the paper strip lie in the outside surface of the cord. Such paper cord has a breaking strength of from 20 to 30% less than the breaking strength of the flat paper strip from which the cord is made;

I have found that this ,decreased tensile 1.0 strength of the twisted cord is due to thepresence of an edge of the paper strip at the surface of; the cord. When tension is appliedV to the twisted cord a tearing component of the force is exerted crosswise of the edge due to the twist 15 and hence the cord ruptures at a lower tension than the fiat paper strip where the total tension on the strip can be applied entirely lengthwise vthereofI I have found that a twisted paper cord so made 20 that the edges of the paper strip are inside the cord and'not at the surface thereof has substantially the full strengthvof the fiat paper strip and in fact the paper cord constructed in accordance with my inventionhas a rupture strength some- 25 what greater, approximately 4%, than the rupture strength of the flat paper strip, this increased strength being due to the increased amount of paper in the cord dueto the twist theref. This relatively large increase of 30 strength vof the cord is highly advantageous in that articles made from the cord, such as bags, for instance. can be made stronger than heretofore, or cheaper for the same strength.

Thus an object of the present invention is the 35 provision of a twisted paper cord of increased rupture strength.

A further object is the'provision of a twisted paper cord wherein the edges of the paper strip of which the cord is composed are disposed in 40 the interior of the twisted cord.

In providing the paper cord of the' present invention the fiat paper strip is rst so folded that both edges of the strip are inside a fold. The

folded strip is then twisted. This method of forming a cord and the cord so formed constitute further objects of the invention.

Another object of the invention is generally to improve the construction of twisted paper cards.

50 Fig. 1 is a perspective view of a twisted paper Flg. 3 is a perspective view of the strip -folding device of Fig. 2. i

Figs. 4;, 5 and 6 are enlarged sectional views taken along lines 4-4, 5-5, 6-6, respectively, of Fig.-2, illustrating the progressive configurations 5 imparted to the flat strip in'the process of folding it.

Fig. 7 is a transverse sectional view of the folded but untwistedcord taken along line 'l-'l of Fig. 2. 10

The twisted cord .IO of Fig. 1 that embodies the present invention is composed of an initially fiat strip of paper l|2, see Flg.` 2, of suitable width and thickness and so formed-that the side edges H and IS of the strip or ribbon are against each other and are disposed in the interior of the cord and hence are not subject to any harmful crosswise or tearing forces when the cord is under tension. The internal disposition of the edges of the strip in the cord are obtained by folding the cord prior to twisting it.

The manner of making the cord i's'illustrated diagrammatically in Fig. 2. The flat strip or .ribbon l2 of paper is contained in a roll 18 and passes through a folding device in the form of a contracting shoe 20 and issues from the end of the shoe in folded form as illustrated in crosssection in Fig. 7. The folded strip thence is vdrawn through the cylindrical passage in a strip compressing die 22 which compacts the folded strip and forms it into cylindrical configuration. The strip thence passes into a rotatable twisting head't, of more or less common construction, and around th`e rolls 26 thereof and receives a suitable twist. The completely twisted cord thence passes to and is wound onto a bobbin or spool 21. The twisting and winding mechanism are or can be of any common desirable construction.

The folding shoe 20 is so constructed that it 40 imparts a triple fold to the initially flat strip of paper. That is to say, the shoe first folds the edge portions of the strip inwardly toward each other, as illustrated in Figs. 4 and 5, so that the edges of the strip confront each other, and then folds the strip along the median line thereof to bring the folded edge'portions of the strip inwardly toward each other -and to dispose the edges4 of the strip inside the third or middle fold.

For accomplishing these results the folding shoe 20 is formed conveniently of a single sheet of suitable material tapered lengthwise of the line of strip advance and having a bottoni 'wall 30 which at the top or entrance end for the and inwardly at the entrance end and overlie' the inner face of the bottom wall sufficiently to permit the free entrance of the paper strip l2 a between them and the bottom-wall and provide generally elliptlcal troughs 34 in which the opposite edges of the paper strip are located. The

' i transverse major axes of the troughs rise in a progressive I'nanner from the entrance to the' exit end of the trough,as illustrated in the successive Figs. 4, 5, and 6, and at the exit end are approximately vertical, as illustrated in Fig. 6, with the reflexed ends 32 of the strip ge'neraily vertical and in closely confronting relation. The transverse width of the shoe thus progressively diminishes lengthwise of the shoe. i

As the flat strip passes lengthwise of the shoe the edges ll and IB of the strip are causedto be curled over in the trough 34 in the manner illustrated in Fig. 5; thereby folding the edge portions of the strip. During further progress of any given portion of the strip along the shoe the strip is foldedadditionally along its median line or at 36, as illustrated in Fig. 6, the folded marginal portions of the strip being subst'antially upright. The completely folded strip as it emerges from the exit end of the shoe has generally the configuration illustrated in Fig. 7, being roughiy circular in cross-section and the edges ll and IS of the strip being disposed inside the third or lmedium bend 36. The folded strip is drawn through the die 22 and has its folds compacted together and rompressed more closely into circular cross-section and is further compacted and caused to be retained in circular cross-section by the twisting of the folded cord.

The cord as thus formed not only is at least equal in rupture strength to that of the fiat strip v|2 of which it is`composed but also is Superior in appearance to the'usual twisted paper cord since no sharp free edge of the paper strip is exposed at the surface of the cord.

I claim: w

1. A high breaking strength round twisted 'paper cord consisting of a paper ribbon having its edge portions folded over, once only, on the same face of the ribbon with the edge portions in closely confronting relation at the middle of the ribbon and the ribbon folded lengthwise in its middle portion to form a solid four ply, only, cord of approximately circular crosssection, thereby disposing the infolded edge portions inside the cord and substantially together with the edges thereof termin'ated in the bottom of the middle fold, the cord'being twisted.

2; A high breaking strength round twisted paper cord consisting of a paper'ribbon shaped into an approximate cylindrical form and having four longitudinal folds of approximately equal' width with the edge portions of the ribbon inside the cylinder, flat, and traversing the diameter thereof and term-inated thereat, the cylinder being twisted.

3. A high breaking strength round twisted paper cord consisting of a paper ribbon shaped into an approximate ,cylindrical form and having its edge portions inside the tube, fiat, unfolded, and 1 traversing the diameter thereof and terminated thereat, the fiat edge portions being in contact substantially their full area across the cylinder,

the cylinder being twisted.

r JOHN E. MILLETT. 

